Magnetic Properties and Local Structure of Fe-Zr-B-Cu Nanocrystalline Alloys

The Mossbauer spectra of nanocrystallized amorphous Fe-Zr based alloys are compared to those of melt-quenched microcrystalline Fe-Zr solid solution in the 4-800 K temperature and in the 0-7 T external magnetic field range. It is established for both cases that besides the well known sharp sextet of the bcc Fe phase (main line) and the broad spectrum component a satellite is also observed. Its hyperfine field shows the same temperature and external magnetic field dependence as that of the bcc structure. The results together with high precision X-ray data for the grain size and lattice parameter as a function of the nanocrystallization temperature make it possible to identify that the satellite is caused by (mainly) Zr dissolved in the bcc structure. Our results do not support the idea that the satellite structure is due to a separate interfacial phase.